The invention relates to a method for optical chassis measurement at a testing station, in which radiation reflected against a surface structure of a vehicle, including at least one wheel and a chassis opening surrounding it, is detected by a measuring device by means of a corresponding sensor system and, through evaluation of position data acquired from the detected radiation, at least the wheel plane and the wheel center point are determined.
A method for optical chassis measurement of this kind has been disclosed by DE 197 57 763 A1 and also in similar fashion by FP 1 042 643 B1. In these known methods, image capturing devices, in particular cameras, are used to detect reference features of the testing station as well as wheel features and chassis features and on the basis of this information, the axis of travel and geometrical data of the wheel and suspension are determined; according to DE 197 57 763 A1, the measurement is carried out while the vehicle is at rest and in the method according to EP 1 042 643 B1, the measurement is carried out while the vehicle is driven past the measuring device. In order to detect the features, ambient light in the region of the testing station is used; the features, in particular of the wheel and the chassis, can be affixed marks or other existing characteristic structures. It is also possible, however, for a special illumination to be provided on the measuring device, for example by means of LEDs; it is also possible for special retroreflecting measuring marks to be affixed to the wheel and the chassis. The prior publications cited also furnish further details regarding the type and detection of geometrical data of the wheel and suspension based on the geometrical information acquired by means of the marks and/or surface structures and they also mention additional patent applications based thereon. In practice, it has turned out that in order to obtain precise, reliable measurement results, it is useful to affix easily detectable marks; although these known systems have on the whole been able to considerably simplify the measurement in comparison to other systems of chassis measurement, adapting these marks to the wheel and chassis does in fact require a not insignificant amount of effort.